Recursion

Herb 4: 2210

Herb was in the entertainment tank watching an old movie: a black-and-white flick called The Blue Magnolia, color and dimension enhanced to make it suitable for a modern audience. If only they could have done something to the plot, wished Herb; as far as he was concerned, it made no sense whatsoever.

Johnston stuck his head above the trapdoor.

“Okay, Herb, we’re on. Let’s go.”

Herb felt his heart thumping in his chest. His hand involuntarily tightened around the hard little machine that Robert had given him, now wrapped in a white linen napkin to prevent Herb cutting himself on its sharp edges.

“No. I thought we had to prepare further. We’re not ready.”

“We’re as ready as we’ll ever be,” Robert replied. “Come on. Don’t you want to see my ship?” He ducked down into the secret passageway.

Herb looked around the comfortable surroundings of his own ship and wished it a sad good-bye. He wondered if they would have white leather and parquet flooring where he was going. He doubted it. He gave a sigh and stepped into emptiness over the trapdoor. His body swung smoothly through ninety degrees as he entered the connecting space between the two ships.

Inside, the secret passageway was longer than it had looked when seen from Herb’s lounge. It echoed and clanked as he walked along it, and beneath those sounds he could feel a shuddering and jarring that suggested the two ships were moving. There was a sudden groaning sound and the passageway itself seemed to deform, twisting this way and that. Herb felt a stab of horror as a hole appeared by his feet and he found himself looking outside, out across to the horizon over a sea of writhing VNMs. That sea was dropping away as the two ships rose higher and higher into the air.

“Come on,” Robert called from the end of the passageway. “I’m recycling the materials of this passageway. The VNMs aren’t going to hang about while you dawdle in there.”

Herb began to run to where Robert waited, holes appearing all around him as he went, cold daylight streaming through the sudden gaps. It was odd: the apparent gravity of the passageway was perpendicular to that of the planet. Which way would he fall if he stepped through a hole? Out, or down? Or neither? Would the gravity field hold strong beneath his feet?

Herb stepped, panting, into Robert’s ship and looked around the interior expectantly.

It was completely empty. A bare room lit with pale blue light from the ceiling. It reminded Herb of a VR room when the entertainment had finished. No, more than that, it reminded him of old images he had seen of film sets when all the props and scenery had been cleared away. Robert’s ship was an empty shell waiting to be filled with the furniture and controls that would make it a real spacecraft.

“Anything wrong, Herb?” Robert smiled faintly as Herb stared around the bare cuboid of the room. Two bumps in the angle between the floor and the rear wall were the only hint that something more to this ship lay beyond the bare surfaces. Herb guessed part of the motors protruded into the room at those points. He looked at Robert in astonishment.

“Where’s the rest of this ship? Or is this another one of your jokes? Is it all hidden away somewhere? Or is this a VR projection?”

“No. It’s another test. Something for you to figure out. By the way, you should step clear of the hatch now. We are about to make a warp jump into space.”

Wordlessly, Herb stepped away from the opening in the floor from which he had just emerged. A panel slid across it, smoothly sealing the gap.

“Okay,” said Robert. “First stop, orbit, to make a copy of your ship, and then we jump right into the heart of the Enemy Domain.”

Herb tilted his head to one side and gazed at Robert appraisingly. “You’re a robot, aren’t you?” he said. “I should have guessed as much. That’s how you always managed to stay one jump ahead of me.”

Johnston nodded once at Herb’s grin. “I can see that’s managed to salvage your ego a little,” he said dryly.

Herb continued around the room, tapping at the smooth grey walls as he went.

“That’s why you don’t need anything in here. No beds or sofas or kitchen or…or…anything.”

“Yes,” Robert said dismissively, then changed the subject. “I’m about to activate the reproductive mechanism on your own ship. Do you want to watch?”

Without waiting for a reply, Robert called up an external view on one wall. Herb saw the final stages of his ship’s warp transition from the planet’s surface, watched it slotting itself back into normal space with a faint shimmer.

Herb frowned suspiciously. “Why are you making a copy of my ship?”

“We’ll be jumping into the Enemy Domain in one of them. We’re keeping the other one as a spare to get us out.” He gave Herb a despairing look. “We can’t stay on mine, can we? There are no facilities here.”

Herb’s voice held a faint tremble. “Why will we need another ship to get out? What will happen to the first one?”

Robert pointed to the sharp little linen-wrapped machine that Herb carried in his hand.

“It will be eaten by that VNM you are carrying. It’s a superfast replicator: makes a copy of itself every point seven seconds. First rule of wiping out a VNM infestation: if it can reproduce faster than you, you have to encircle it and work inwards. Very time-consuming, and you run the risk of some of the infection escaping through the gaps in your net. But if you can reproduce faster than the enemy, then you start in the middle and work outwards. We’ll be chasing the infestation, but we know we will catch it in the end.”

“What will happen to me? Will I be on the ship?”

“You’ll be okay,” said Robert. “That machine you’re carrying prefers to convert nonorganic materials.”

“Oh.”

Robert gave Herb a significant glance. Herb ignored it. Looking outside, he could see that his ship was warping and deforming. A long bulge formed along the upper surface as a second ship began to grow.

“Look at that,” Robert said, pointing to Herb’s pregnant spacecraft. “You humans astonish me sometimes. Every adult, every child even, has access to machinery that can reproduce in that way. Haven’t you ever wondered why the universe isn’t already choked up with your junk?”

Herb looked at him in puzzlement. “But it’s illegal to make unauthorized copies. You need a license to operate a VNM on Earth. They need materials with which to make copies of themselves: you could be stealing someone else’s resources.”

Robert laughed. “It’s illegal to convert planets into masses of flickering VNMs, but that didn’t stop you giving it a try.”

“So? You caught me and stopped me.”

“And I’ve caught twenty other young men and women before you. Did you ever hear of Sean Simons? He was a young man, just like you. Rich father, too much sense of his own importance. Bit more malice, mind. He deliberately set about converting a planet.”

“Doesn’t sound familiar.”

“Really? Check the news files. He went missing.” Robert looked at Herb darkly. “I know where he is, though,” he added softly.

Herb felt a little chill, but it quickly dulled. The featureless pale blue room had assumed the aspect of a place apart from reality: a waiting room where they paused while the main events prepared to take place.

“We can’t catch everyone, though. Hasn’t it occurred to you that there may be deeper forces at work here? Every human with a gram of common sense can get hold of a warp drive and a self-replicating machine. You could fill the galaxy with little silver cigars before teatime.”

Herb was impatient. “I know; that’s what the EA is for. That’s what we’re working to prevent now, isn’t it?”

Robert looked at Herb for a moment then shook his head in disbelief.

“No. I give up. You really don’t see it, do you?”

Outside, the bulge in the top surface of Herb’s ship had grown a lot larger. The second ship would soon begin tearing itself free.

They were moving through space, the two ships accelerating away from Herb’s accidentally converted planet. Herb felt an odd pang of loss as he saw that dull grey disk getting smaller as they moved faster and faster. Just behind them, his pregnant spaceship went through the final throes of labor.

Robert stood at Herb’s shoulder, looking on appreciatively.

“What’s the gestation period?” he asked.

Herb smiled with paternal pride. “Twenty-five minutes under optimal conditions. And it can do that every two hours, assuming an appropriate source of construction matter is at hand.”

“Oh, I know where there is one,” said Robert. He looked back at Herb’s ship and then clapped his hands together.

“Oh well. Five more minutes until the ships have separated. Then we jump.”

“Is that it?” asked Herb. He suddenly needed the toilet, and he was acutely aware there was nowhere to go on Robert’s ship. He also wanted to change his clothes. Silk pajamas and a pair of paper slippers may make good ship wear, but he felt incredibly exposed at the thought of landing dressed like that in the middle of the Enemy Domain. He needed body armor. An ABC suit. It was too late for all that.

Herb’s mouth felt dry. “Don’t you have any advice for me?” he asked plaintively.

“Yes. Just do as I say.”

“Oh.”

Herb licked his dry lips. So this was it. He gazed around at the illuminated walls of the spaceship, looked through the viewing field at the receding disk of his abused planet, and wondered sadly how it had come to this.

He thought back to the day that he had left Earth. Walking across the dew-soaked lawn beneath a cloudless blue April sky that seemed to go up forever. His spaceship had sat waiting on the grass ahead of him. Herb had paused for a moment to glance around at the beautiful spring morning. The sight of his father’s house, the green copper dome on its roof, the cream-painted stone walls and the windows reflecting the early morning sunshine. What could he find in space that couldn’t be equalled or surpassed by that morning?

Now he wondered: would things have been different if he hadn’t taken off then?

Herb didn’t know. All he knew was that in three minutes he would be jumping to almost certain death. He looked miserably around Robert’s ship again. The pale blue room, the dark viewing area…

He felt sick.

Herb’s spaceship had separated into two new ships. Two creamy white boxes that tumbled slowly through space behind them. Robert looked on, impressed.

“Almost perfectly balanced,” he whispered. “Only a fraction of a gram’s difference between the two. And only a total mass of one point seven grams lost in the process.”

Herb nodded in terrified agreement. The two ships that now floated behind looked identical to him. He would have expected no less, of course. The twin ships began to drift apart.

“What now?” asked Herb.

“One’s going back to your converted planet to replenish its mass. We’re going to board the other and make the jump into the Enemy Domain.”

“What about restoring our ship’s mass?” asked Herb frantically, hoping for a way to delay the impending jump. “It won’t be working at optimal efficiency at only half mass. What if we’re attacked? The walls will be too thin to deflect any attack.”

Robert gave a little laugh. “The thickness of the walls will make no difference when the Enemy Domain attacks. The ship may as well be made of rice paper for all the protection it will give us.”

There was a faint sigh and the floor hatch opened up. Robert gestured towards it.

“Okay, Herb, our new ship has docked. After you.”

Herb felt his stomach sink. His hand tightened around the sharp little VNM Robert had given him.

He stepped into the hatchway. Robert followed.

The replication was very good. The ship was identical to the original, right down to the copy of The Blue Magnolia, now coming to its conclusion in the entertainment tank. Herb ran his hand across the white leather of the sofa. It felt just as soft, just as cool. Did the ship carry spare leather, he wondered?

He could almost believe that the replication hadn’t taken place, that he was back on his original ship, but of course there was no original ship now. It had split into two identical copies, each of half the original mass. A display had lit up on one wall informing him of the fact. If he cared to, he could examine the status of the fission right down to the subsystems level. Herb didn’t care.

Robert was at work meanwhile altering the ship’s interior, opening viewing fields in all four walls and the ceiling. Smaller viewing fields opened in the floor, interspersed with screens across which multicolored lines and patterns scrolled. Status screens. Herb found himself standing in a viewing field, a silver puddle of light shimmering around his ankles.

“Sit on that sofa,” said Robert, pointing to the one opposite. “I’m arranging it so we can see everything from the conversation area.”

Herb stepped out of the puddle and sat down opposite Robert.

A sudden jerk pushed him back into his seat. It was followed by two more that knocked him over to the left.

“Sorry. I’m just trying to get the gravity field adjusted. We barely got enough exotic matter in the division to enable the warp jump. There’s not much left over to maintain gravity.” Robert grimaced. “If the enemy gets us in a steep enough gravity gradient, we’ll be smeared across the inside of this ship like butter.”

“Thanks,” said Herb, turning pale.

“Actually, that won’t happen,” Robert said happily. “I forgot. The hull is so weak after the separation, the ship will crumple along with us. It will be like sending a bag of blood through a mangle.”

Herb moaned.

Robert paused in his work and looked at him.

“Don’t worry, Herb. There’s nothing to worry about. We’re going to win. Just remember, the EA AI is far more intelligent than anything in the Enemy Domain. It’s not about the Enemy’s greater strength, it’s about the intelligent application of force. Ask any swordsman: the point beats the edge every time.”

“I’m not comforted,” said Herb.

“Well, I tried.” Robert sighed.

Herb was shaken around on the sofa by another series of violent jerks. Throughout the sudden shuddering motion he could sense a steady acceleration, usually hidden by the internal gravity field.

A mapping of the Enemy Domain suddenly appeared above their heads, a cloud of silver and rose with significant features picked out in gold and blue. Robert gazed up at it and nodded in satisfaction. It vanished and Robert turned and looked at several of the viewing fields he had opened up around the ship, checking that everything was okay.

“Have you got your VNM?” he asked Herb, who wordlessly held it up. Tiny scarlet drops of his blood shimmered on the edge of the sharp metal points that had cut their way through the thick linen cloth in which the machine was wrapped. Herb hadn’t even felt any pain. The ship’s gravity cut out again and he felt himself pushed back against the seat. Herb wondered why it was necessary to travel quite so fast. What was the point when they were about to make a jump? They would only have to slow down again at the other end.

“Can you think of anything we’ve forgotten?” Robert asked, his gaze still traveling from viewing field to viewing field.

“No,” said Herb. He wished he could think of something.

“Okay, here we go, then.”

When he was younger, Herb had thought he knew all about superluminal travel. He was now just old enough to admit that he didn’t. The AIs insisted that the methods used were beyond human intelligence, and no human had yet been able to contradict them. Herb did understand the basic principles, however.

He knew that special relativity dictated that it was impossible to travel faster than light in an area of flat space-time; however, he also knew that general relativity placed no restrictions on two regions of flat space-time moving apart at greater than light speed. The equations describing a warp field that could move a region of flat space-time faster than light had been derived long ago, at the end of the twentieth century, before even the first AIs had appeared. Human intelligence had shown that exotic matter was required in order for the fields to exist.

It was fair to say that contemporary AIs insisted that the superluminal travel they provided was far removed from those “trivial” equations, but they did agree on two particulars.

First, the warp drive required exotic matter.

Second, it involved moving a region of flat space-time around the universe.

Herb was in such a region now. And the ship’s velocity within that flat region must be considerable.

Herb wondered why.

They inserted themselves back into regular space-time. The forward-viewing areas lit up with brilliant white light. Those to the rear of the cabin darkened.

“Atomic explosion,” Robert said in some surprise. “Their detection systems are better than I expected, as are their reactions. If we were at rest relative to the warp, we’d have been right at the heart of that. As it is, we’ve probably got the length of this sentence before they get a lock on us again. Ah! Got it!”

“Got what?” called Herb.

“The security web monitoring this system. I’ve altered our status flag to “friendly object.” See what I mean when I talk about superior intelligence? It’s not about having a stronger hull or more powerful weaponry. The battles of the twenty-third century aren’t fought by AIs. They’re fought inside AIs.”

“Wha-?”

The viewing screens glared brightly again. This time the ceiling darkened.

“What was that?” Herb shouted.

“Another atomic. There is a second web watching the first, monitoring its integrity. It noted our changes and launched another attack. I jumped us forward a couple of light seconds to escape the blast. Don’t worry, I’ve also tackled the second web.”

“Does that mean we’re safe now?”

“We’ve always been safe. If, however, you mean, ‘Will we be attacked again?’ then I’m afraid the answer is yes. We can’t stay hidden forever. The surveillance systems will take counter-countermeasures against our countermeasures.”

Johnston reached into his breast pocket and pulled out his white handkerchief. He flapped it twice in the air and then spread it flat on the sofa next to him.

“Okay, Herb. Now to replenish this ship’s mass. The planet below has been converted by saliva nanotechs. Are you aware of the term?”

“Yes.”

Robert felt in a pocket and pulled out a silver cigar-shaped machine which Herb recognized as one of his own VNMs, placing it on the white handkerchief.

“The term ‘saliva nanotech’ was coined by Katie Kirkham,” he explained.

“I know,” said Herb.

“It describes a simple VNM, the principal use of which is to convert matter into suitable building material for other VNMs. It obviates the need for a stomach or other such device being built into the principal VNMs in an area, thus speeding up the rate of replication, and hence construction.”

“I know,” said Herb. “I said I’d heard the term before.”

“Drop a few saliva nanotechs in a suitable area, leave them for a while, and when you return you have ready-processed material for other VNMs to use.”

“I know.” Herb was becoming quite angry. “I also know that you use them with caution. You don’t want them getting away and converting everything around. And that you have to tailor them to the prevailing conditions. Those set to find and reclaim silicon would be no good in water.”

Robert ignored him. He waved a hand at the VNM he had taken from Herb’s accidentally destroyed planet.

“This machine that you built does its own conversion. Its silvery color is due to the prevailing mineral content of the area of the planet where it was released. If someone were to travel over your converted planet, I imagine the color of the machines and makeup of the machines they saw would vary according to the former local geology.”

“That’s right. I know. I designed it.”

Robert looked a little surprised.

“Surely you mean, you purchased the design for a type six self-replicating machine and made the appropriate modifications?”

Realization flashed through Herb. It finally hit him. He finally understood.

“You’re doing this deliberately, aren’t you? Every time things get tense. You do your best to get me annoyed, just to take my mind off things.”

Johnston smiled. “That’s right, Herb.”

The smile widened. Herb counted ten teeth, gleaming against the pink flesh behind Robert Johnston’s dark lips.

“I didn’t want you concentrating too hard on the fact that we were about to descend onto an Enemy planet to steal some of its building blocks for our ship, or that this region of space has been seeded with security nanotechs, several of which have attached themselves to our ship and are currently at work converting our hull into more security nanotechs. I’d guess we have about ten minutes before this lounge dissolves before our eyes.”

“Don’t they think we’re on their side like everything else in here?”

“No. Too small. They’re not part of the security web. They’re just here as another line of defense in case the web doesn’t work. It’s a very effective passive defense, too: they’ll eat anything that isn’t labeled as inedible.”

“Well, label us inedible.”

“I’m doing that even as we speak. They’re transmitting a code using a public key system. Obviously they inherit the key from each other when they replicate. If I can figure out the key and send back a message encoded using the private key, they should trust us.” He closed his eyes.

“Come on,” said Herb, squirming nervously on the sofa. “They’ll be through any minute now.”

Robert opened his eyes in puzzlement.

“Oh, sorry. I solved that problem while I was explaining it to you.” He tapped his head and rolled his eyes. “I must remember to keep you informed. No. I was just working out the coordinates for the transition to the planet’s surface. Okay. We’re jumping now.”

Herb clenched his left fist in frustration. His right hand was too sore from clutching Robert’s machine.

“What is the point of me being here?” he complained. “I can’t think fast enough to beat the Enemy. I don’t know what to do, anyway.”

“I need you to press the button that makes that VNM reproduce, remember?” Johnston replied, pointing to Herb’s right hand.

Herb looked at him in disbelief. “Is that it? Couldn’t you place it on a timer or something?”

Johnston shook his head slowly and sighed. “Oh, Herb. Why won’t you trust me? There are some aspects to this mission that only a human can accomplish. If you will just be patient, you’ll see what they are. Okay. Let’s jump.”

There was a sudden discontinuity and then they were hovering above the surface of the destination planet.

“Nighttime,” said Herb.

“No,” muttered Robert, distantly. “We’re in interstellar space. This planet has no star. It wanders alone.” He nodded thoughtfully. “There are more of these planets than you might expect; they’re just incredibly difficult to find. Hold it. I’ll adjust the view so you can see better.”

Virtual daylight filled the ship as he adjusted the viewing field’s output, pushing everything into the visible spectrum. The ship was floating over a silver sea studded with rocky columns and promontories that trailed away from a row of cliffs. Everything had a spongy, desiccated look.

“They’ve gone for the metals first,” Robert murmured. “The sea below is a nickel iron alloy. This planet must have been mostly metal. Come on, let’s feed the ship.”

They began to descend, the metallic sea appearing to expand as they sank toward it.

“How long does it take this ship to absorb matter?” Robert asked. He glanced up and backward at a viewing field located just behind his right shoulder.

“It depends,” answered Herb. “Usually it takes it on board and plates it in a layer just inside the hull. It’s gradually transported from there to the necessary locations as part of the ongoing maintenance and repair procedure.”

Johnston nodded. “I guessed as much. And how long to take the necessary material on board?”

“A couple of minutes, if that.”

“Good. We’ve got just about enough time, then.”

“Just about enough time for what?” Herb asked. Something about the way Robert spoke brought the never too distant feeling of fear in his stomach back to the fore.

The robot did something to one of the fields. The view focused on something, pulled back and refocused, pulled back again and refocused once more.

“Just enough time to get away from that,” he murmured.

Herb gazed at the viewing field in horror. From the high vantage point of the virtual camera he could finally make out what was going on. The sea over which they floated was crystallizing in a circle around them. It was as if a rime of white frost was settling on the surface of the gently moving liquid metal and freezing it into a rapidly tightening noose of ice. Herb could see their ship, clearly marked as occupying the center position. The bullseye.

He became aware of something else. A slow, deliberate movement around the edges of the sea. A second viewing field focused in on one particular section, and Herb was momentarily thrown by the contrast within his range of vision, between the quiet calm of his lounge-the polished wood sculpture and the white vase with the gentle pattern of flowers embossed around the rim, the parquet floor and the cool eggshell finish of the ceiling-and the frantic battle outside. In the midst of the calm of his lounge, there on the viewing field, he could see the little machines outside forming themselves from the sea of metal, sucking its material as they bulged and then split into two.

“Reproducing once every eight point two seconds,” said Robert. “Pretty impressive really. Well, when you consider the limitations of the intelligence we’re up against.”

“They’re going to surround us,” whispered Herb. “We’ll be trapped.”

It seemed inevitable. He could see the thickening cloud of the tiny machines as they rose into the air, an angry cloud of insects that seemed to pull a silver curtain up from the surface, such was their density-a silver curtain that promised to engulf them. It was as if a sack was being lifted up and around and over the ship.

“Shouldn’t we run now?” asked Herb.

Robert shook his head. “Don’t worry. I’ve worked out their rate of reproduction. We’ll get away with fourteen seconds to spare.”

Herb said nothing to that. There was nothing to say. All he could do was sit and stare at the rising cloud of little machines, each about the size and shape of a saucer. They spun and shimmered in the virtual light. Their underside was darker than the top and scored with a series of concentric circular grooves. When they fissioned, it was into two saucers joined along their tops, grooved undersides facing outward.

“How do they know we’re here?” asked Herb. “I thought we were masquerading as friends?”

Robert grinned. “Oh Herb. I keep telling you: the intelligence behind the Enemy Domain is convinced of its own superiority. It is in the nature of such individuals to trust no one else. How could they trust an inferior? This is a paranoid region we have wandered into. It has security systems piled upon security systems. We will never deceive all of them. We can only hope to fool a few of them for just long enough.”

He glanced at his wristwatch. “One minute until we leave.”

One minute. It seemed an eternity to Herb. He was sure that would be too long. The cloud of machines rising from the circumference of the sea was now diminishing. Those machines closest to the planet’s surface began to change shape, their circular edges flattening off as the saucers became octagonal. The machines began merging together along these flat edges. As they did so, the gaps left between the shapes began to widen, the body of the plates narrowed and thickened.

“They’re forming a mesh. We’ll be trapped in the cage.”

Herb licked his lips and wished he hadn’t spoken. His voice sounded high-pitched and cracked.

“We’ll be fine,” said Robert, rising to his feet. “Thirty seconds and we’ll be gone. There’s nothing to worry about here.”

He picked up the silver machine, the modified VNM he had taken from Herb’s planet. Its legs waved gently as Robert carried it across the room to the hatchway.

“The real problems will emerge the deeper we travel into the Enemy Domain. You see, the Enemy isn’t stupid; it will learn from its mistakes. We won’t be able to defeat it the same way twice.”

The hatch slid open. Robert held the silver machine over the space in the floor for a moment. Its legs began to wave a little faster as it sensed the vast pool of raw materials beneath it.

Robert glanced across to Herb.

“You should be pleased with yourself, Herb. If you should die, think this of yourself. There is a planet, in some distant sky, that will be forever a part of your creation.”

He let go of the machine and it tumbled through the hatch, its legs flickering up and down like the needles on a sewing machine.

Above them, a viewing field showed what would become the roof of their cage now closing over them as a faint mist of silver saucers. The hatch slid shut. A gentle note sounded in the cabin.

“Okay, we’re full. Off we go.”

Herb let out a huge sigh. How long had he been holding his breath? The silver sea below them began to recede; the thin misty roof above them approached closer and closer. They burst through the insubstantial cloud of silver saucers without any difficulty and began to accelerate into space.

Herb felt a wave of relief that was quickly overtaken by anxiety again. They had escaped this trap, only to have Robert jump them deeper into the Enemy Domain.

“I don’t think I can take much more of this,” muttered Herb, seriously.

Robert eyed him closely. “Of course you can,” he replied. “I’m monitoring all your vital signs. Your stress levels are well within acceptable limits.” He raised his eyebrows just a little. “All right, your blood pressure is a touch too high, but if you were to reduce your salt consumption, you’d be okay.”

He sat back down on the sofa. “Warp jump in twenty seconds. We’re going to try and lead them off on a false trail. We don’t want them waiting for us with any nasty surprises when we break back into normal space.”

“I thought it was impossible to track someone through warp space.”

“It is,” said Robert. “Come on, Herb, think laterally. There are ways and means.”

“Is this another one of your ways to keep me calm? Take my mind off things?”

“That’s right. Here’s something else to think about, too. Why did I drop that machine of yours on the planet?”

Herb gave a puzzled frown. “To reproduce, of course. I would have thought that was obvious.”

“Of course, Herb. Silly me for thinking I could tell you anything.”

The ship was accelerating again, building up tremendous speed.

“Do you think they’ll try to nuke us when we arrive again?” asked Herb nervously.

“Of course,” replied Robert. “Okay. Jump in five seconds. Four, three, two, one…”

They jumped.